import tkinter
import time
import random
class Ball():
    def __init__(self,canvas,color):
        self.canvas=canvas
        self.id =canvas.create_oval(0,0,15,15,fill=color)
        level=[-9,-7,-5,-3,-1,0,1,3,5,7,9]

        canvas.move(self.id,254,100)
        self.x=random.choice(level)
        self.y=random.choice(level)
    def draw(self):
        canvas.move(self.id,self.x,self.y)
        pos = canvas.coords(self.id)
        if pos[3]>=600:
            self.y=-3
        if pos[1]<=0:
            self.y=3
        if pos[2]>=600:
            self.x= -3
        if pos[0] <=0:
            self.x = 3



tk=tkinter.Tk()
tk.title("弹球游戏")
canvas=tkinter.Canvas(tk,width=600,height=600)
canvas.pack()
tk.update()

ball = Ball(canvas,"red")
ball2 = Ball(canvas,"blue")
while 1:
    ball.draw()
    ball2.draw()
    tk.update_idletasks()
    tk.update()
    time.sleep(0.001)
